In my studies of California Native Cultures, I was often surprised
to keep coming upon plant-use references documenting "fish
poisons". In widening my search, I became aware that most
indigenous cultures across the Americas and indeed on all continents
in the temperate areas of the world, used poisonous plants to
catch fish. Below is a small sample of fish poisons and the indigenous
peoples who used them. Further study will present the reader with
a much greater breadth of information.

Fish poison plant families of the world.

Most fish poisons, also called icthyotoxins or piscicides,
occur in several related plant species. A variety of chemicals
found in these plants will stun fish when it passes through the
gills or in some cases ingested. The fish then floats to the surface
for easy capture.

The active ingredient is released by mashing the appropriate
plant parts, which are then introduced to the water environment.
Poisoning was generally done in stagnant pools or slow-flowing
streams and rivers, that allow the pounded bark, leaf, seed, root
or fruit, to concentrate its power without being washed away or
diluted by a strong current. Sometimes streams would be partly
blocked to slow down the water flow. Gathering the fish was usually
done by hand, but baskets, spears and nets were sometimes employed.

Although primarily used in fresh water areas, Australian Aborigines
and Californian Indians also used this technique in saltwater
environments for octopus and low-tide shellfish fishing as well
as for catching fish trapped in inter-tidal pools.

This ethnological report from Cape York Peninsula, Queensland,
Australia, shows that with some Native Peoples, the cultural and
material world was not separated:

A secret, sacred song of the Pascoe River bora (initiation
cult) was sung by 60-year-old George Morton accompanying himself
with his own drum. The singer was born a Kandyu but married a
Wutati woman who was the daughter of one of the great Wutati
bora singers who handed down the entire repertory of ancient
bora songs to him. This song tells of a turtle that used a medicinal
vine as a poison to catch fish in a rock pool at low tide.

The use of plant poisons to catch fish is still used in many
places in the world today. In Guyana, fishers pound the root of
Lonchocarpus on logs fallen across a stream and allow the juices
to drip down into the water. Brazilian gold miners, who probably
learned the technique from the displaced Yanomami Indians of the
Amazon, also toss pulped plant material into a very slow moving
stream where the fish would surface down stream and be washed
into a net set in place by the fishermen.

Grating Barringtonia seeds on the island of Tanna
for use as fish poison.

The Carib Indians, who live along the Barama River also in
Guyana, use a modified technique. A ball of bait is made from
baked Cassava (Manihot esculenta) mixed with the pounded toxin-laced
leaves of Clibadium. The small balls are thrown into the river
where the fish swallow the balls whole. As with the previous methods,
the stupefied fish floats to the surface for easy capture.

H.E. Anthony reported another example of fish poison use in
South America in 1921.

"Another poison which is extensively employed by the
Jivaros is barbasco (a common name for any plant used as fish
poison), a jungle vine or creeper, which is put into the rivers
to secure fish. A great pile of the plant is beaten up on the
rocks until it is a pulp, and after the Indians have stationed
themselves down-stream, some of their number throw 2-3 hundred
pounds of mash into the river and the fishing begins. The fish
are killed and float down, belly up, to be gathered in by the
Jivaros, who see them as they pass.

So potent is this juice that large streams may be poisoned
by this relatively small amount of barbasco and under favorable
circumstances fish are stricken for a distance of three miles
down-stream."

The pandemic need to find plants that work well as a soap,
i.e. the ability to make lather and suds when agitated with water,
has been pursued by most native cultures. The experience of using
various plants selected for their soap like properties, led to
the universal discovery that chemicals from these plants would
also stun fish when used in a specific circumstance.

The two primary chemicals that occur in most plants used for
stunning fish are saponin and rotenone.

SAPONINS

Saponins normally break down in the digestive system and must
enter the bloodstream to be toxic, but fish take in saponins directly
into their bloodstream through their gills. The toxin acts on
the respiratory organs of the fish without affecting their edibility.
Saponins also cause the breakdown of red blood cells that help
the toxin to spread quickly. Even though the effects of the poison
are powerful, they are not usually fatal. Fish that are washed
away into untainted water revive, and can return to their pre-toxic
condition. Because of this, the fishermen would have to gather
the stunned fish quickly as they floated to the surface.

Saponins are one of a group of glucosides found in many plant
species with known foaming properties when mixed with water. Saponins
lower the surface tension of water allowing the formation of small
stable bubbles. The amount of foam created by a crushed plant
sample, shaken with water in a jar, is a good indication of the
amount of saponins present.

Saponins have been used in modern times in the manufacture
of fire extinguisher foam, toothpaste, shampoos, liquid soaps,
and cosmetics and to increase the foaming of beer and soft drinks.

Plants containing rotenones are the second most utilized as
a fish poison. Rotenone is an alkaloid toxin, in a group called
flavonoids and stuns fish by impairing their oxygen consumption.
The plant is toxic only to cold-blooded creatures and is found
almost exclusively among the family comprised of legumes (Papilionaceae,
Mimosaceae, Cesalpiniaceae). Rotenone is also used today as an
insecticide.

Professionals today, to control fish populations or to eliminate
alien or destructive species, use the same plant toxins: saponin
and rotenone. Practicing primitives may be eager to experiment
with the techniques listed above, but great care must be used,
as the toxins are not selective and will eliminate all fish in
the water where it is introduced. Keep in mind what is down stream
and may be affected by these poisons. These chemicals will generally
break down in sunlight. If you choose to use this technique, be
aware that fishing with poison (even natural poison) is illegal
in most states. Check your local laws.

A Lesson From the Amazon

Professor Sir Ghillean Prance relates this story from an expedition
in which he was a member in the 1960's:

"The Maku Indians of the upper Rio Negro region of
Brazil are well known for their fish feasts, where they go to
a small river and catch a large number of fish by using fish
poisons. The time I arranged to watch one of these, we were told
that we must set out into the forest early in the morning. After
two hours of a very fast walk we came to a small stream and I
was glad to have arrived, but our leader said 'not here'. We
came to another stream an hour later just to be informed the
same again. This process continued for about eight hours when
finally the chief proclaimed that this was the correct stream.

We were almost too exhausted to observe the preparations
as the men built a frame over the stream and placed their sacks
of the fish poison leaves (Euphorbia cotinifolia). Meanwhile
the women stirred up the muddy stream and the men began to beat
the leaves so that the plant juices dripped down into the water.
Very soon fish began to float to the surface and were gathered
up by excited women and children.

We had a banquet as all the fish were roasted on fires
and eaten. I asked the chief why we had to walk so far to carry
out this operation. The answer I received was that they had poisoned
fish in the first stream two moons ago, in the second five moons
ago etc., until I got a complete description of when each stream
had been used. He then informed me that if they poisoned a stream
too frequently there would not be any fish left.

How unlike the fisheries off the British Isles, Japan or
Newfoundland where fish like cod have been mined almost to extinction.
These Indians are aware that you manage such natural resources
rather than over-exploit them to extinction. Could we not learn
from this harmonious co-existence with nature and become better
managers and less greedy about our natural resources?"

REFERENCES

Anthony, H.E., 1921 Over Trail and Through Jungle
in Ecuador
National Geographic Magazine, October 1921, Pgs. 328-333

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